Overland Park, KS (January) - Finally, in many parts of the country, signs of spring are becoming evident and horse owners and riders are taking to the outdoors to enjoy the sunny, warmer weather. While horse owners are thinking "outside," veterinarians are thinking "inside," as spring also marks the beginning of the parasite season and the need for early deworming.

"Plain and simple, spring deworming is essential to maintaining healthy horses," said Dr. John Tuttle, a veterinarian and manager of Professional Services for Fort Dodge Animal Health. "If a horse is not dewormed early in the spring and kept on a regular deworming schedule, microscopic parasites can invade the animal's digestive system and cause a wide range of problems including poor performance, weight loss, organ damage or even death."

Veterinary experts concur that horse owners are best able to protect their animals once they are familiar with these parasites' life cycles, and better understand how horses become infected. Many varieties of parasites rely on horses as their hosts, and their life cycles can start at different times of the year. The warmer spring and summer months are the optimal time for infestations by many parasitic worms, making spring deworming a vitally important equine health-care practice.

The parasite life cycle starts in the pasture, where parasite eggs are shed in the horse's feces. In a limited pasture area, millions of eggs are deposited into the soil. The larvae migrate out of the feces and onto nearby grass, where they are then swallowed by grazing horses. Due to the overwhelming amount of larvae in the pasture grass, it is nearly impossible for a horse to escape exposure.

Once ingested, the larvae then grow through several stages and, depending on the species, travel throughout the body, damaging the stomach, intestines, blood vessels, liver and lungs. Once parasites reach adulthood, they begin producing eggs that are deposited back into the pasture through the horse's feces - starting the life cycle again.

"Before horses take to the outdoors and spend time on pasture, owners must take precautions to protect their animal from these parasites. Your best shot at protecting your horse is with early spring deworming," said Tuttle.

While there are several types of parasitic worms that are cause for concern, foremost among these life-threatening invaders are the small strongyles.

"They have been termed 'Parasite Public Enemy #1' because they are the most common - affecting virtually every horse - and have the potential to cause the most devastation," reported Tuttle.

Small strongyles (Cyathostomum, Cylicocyclus and Cylicostephanus spp.; Gyalocephalus capitatus) are considered especially dangerous because of their ability to burrow into a horse's intestinal wall, where they further develop. At this stage, they are referred to as "encysted cyathostomes," and can remain in these fibrous bubbles in an inactive state from several weeks up to one year or more.

Large numbers of encysted small strongyles can suddenly and unexpectedly emerge from the intestinal wall, releasing into the horse's system metabolic excretory products that the larvae have been producing within the cyst. According to parasitologists, the release of these dangerous toxins can cause a variety of intestinal problems, including: diarrhea, anemia, severe and rapid weight loss, colic, fever and even death.

"While there are a variety of dewormers on the market that rid horses of most parasitic worms, only QUEST® Gel (moxidectin) kills these dangerous encysted small strongyles in a single dose, before they emerge and can release metabolic wastes into the horse's system," explained Tuttle. "Additionally, this helps reduce the number of eggs that are shed in the horses' feces, which thereby keeps pastures clean significantly longer than when using other common dewormers."

QUEST® Gel, introduced over five years ago, contains the active ingredient moxidectin, which is distinctly different from conventional ivermectin-based products. Single-dose QUEST is formulated as a clear oral gel that is highly acceptable to horses, and controls the most common and economically devastating worms and bots, with just four treatments a year. With its easy-to-use syringe, QUEST® Gel ensures accurate dosing with no waste or spit-out.

According to Tuttle, horse owners should consult with their veterinarians in the spring to develop a year 'round parasite control program that includes regular deworming and other important preventive measures.

Parasite experts also encourage horse owners to incorporate certain management practices in their maintenance routines to significantly reduce the number of internal parasite eggs and larvae in pastures.

These recommendations include:

- Removing feces from the pasture at regular intervals - twice a week if possible.
- Providing a feed rack, and not placing feed directly on the ground.
- Grouping pastured horses by age, to avoid exposing youngsters to heavy larval populations.
- Eliminating overstocked pastures, which forces horses to graze near feces. If possible, provide at least one acre per horse.

For more up-to-date information on parasites, parasite control and QUEST® Gel, visit www.questgel.com.

Fort Dodge Animal Health, a division of American Home Products Corporation, is a leading manufacturer and distributor of prescription and over-the-counter animal health care products for livestock, companion animals, swine and poultry. American Home Products is one of the world's largest research-based pharmaceutical and health care product companies and a leader in the discovery, development, manufacturing and marketing of prescription drugs and over-the-counter medicines.